PC cluster 3 showed increased expression of Gif (gastric intrinsic factor), Cd81, a tetraspanin family member known to mark the response to gamma-irradiation and correlated with the expression of ISC- and proliferation genes28, and Prom1 (also known as CD133), a well-established colon cancer stem cell marker29. This evidence concerns the gene PROM1 and colonic neoplasm.